JP2860093B2 - Information storage medium playback device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an information storage medium reproducing apparatus, and more particularly, to an information storage medium such as a digital audio disk which records time information together with main information. The present invention relates to an information storage medium playback device suitable for playing back information. 2. Description of the Related Art An example in which main information and time information are recorded on a track of an information storage medium is disclosed in JP-A-60-43.
As stated in Japanese Patent Publication No. 270, as main information,
There is a compact disk (hereinafter, referred to as a CD) in which a digitized audio signal is recorded on a spiral track so as to be optically readable. As described in the above-mentioned publication, the recording format of the CD is constituted by a predetermined small frame unit and is continuous. The small frame has a period of about 136 μsec. It consists of a frame synchronization information part, a subcode information part, and a data part containing music information of main information. The subcode information portion is composed of 98 small frames and has a period of about 1
It includes time address information and the like in units of large frames of 3.3 ms. As described above, when a signal is reproduced from a disk on which digital signal information is recorded by means of an optical system or the like, the reading position on the disk by the information reading means is easily moved by an external force or the like, so that it is inadvertent. If it is moved, the reproduction information may be omitted or duplicated. For this reason, in the above publication, when the information reading means is accidentally moved by an external force or the like, the position of the information reading means and the rotation speed of the disk are controlled to bring the information reading means to the original reproduction position. It was configured to be moved. [0004] In the above prior art, when the information reading means is accidentally moved by external force or the like, the position of the information reading means is controlled to a regular reading position on the disk. In the case where the information read by the information reading means is reproduced between the time when the information reading means is accidentally moved and the time when the information reading means is returned to the normal reproduction position, the information reading means does not omit or overlap the reproduced information. There is a problem that an abnormal reproduction state such as a noise in reproduction information or a temporary suspension of reproduction occurs until the reproduction information returns to a normal position. [0005] It is an object of the present invention to solve the above problems by suppressing abnormal reproduction states such as noise and temporary suspension of reproduction during a period from when the information reading means is accidentally moved to when it returns to a normal position. An object of the present invention is to provide an information storage medium reproducing device with improved vibration resistance. An object of the present invention is to write main information data reproduced from an information storage medium into a memory, and to provide discontinuity in time information reproduced together with the main information data from the information storage medium. Occurs, the writing of the main information data reproduced from the information storage medium to the memory is stopped while the information reading means is moved to the reading position before the occurrence of the discontinuity from the time when the discontinuity occurs. This is achieved by reading from the memory at a fixed period of the sampling frequency. Since the memory for storing the reproduction data from the information storage medium stores the reproduction data for a certain period of time,
The data is read from the memory during the time when the reading position of the information reading means is moved from the time when the discontinuity of the time information occurs, and the stored data is read. As a result, data to be converted from digital to analog can be reproduced continuously without discontinuity. An embodiment of the present invention will be described below by taking a compact disc player as an example. FIG. 1 is a block diagram showing an embodiment of an information storage medium reproducing apparatus according to the present invention, wherein 1 is a compact disk, 2 is a motor for rotating the disk, and 3 is a device for optically reading signals on the disk. A pickup 4 is a preamplifier circuit for amplifying a signal from the pickup 3 to obtain a reproduced signal and a track and a focus error signal from the disk. A reference numeral 5 is a track from the preamplifier circuit 4, a focus error signal and a motor from the disk signal processing circuit 6. A servo circuit for servo-controlling the pickup 3 and the motor 2 by the speed detection signal 2, a read-in signal from the disk 6, EFM demodulation and error detection and correction according to the recording format, and a quantization bit number 16 bits , The sampling frequency of 44.1 kHz
A digital signal processing circuit for alternately outputting channels (L and R channels), and obtains a speed detection signal of the motor 2 from a frequency variation of a synchronization signal reproduced from the disk 1,
Further, it includes a timing circuit for performing these operations. Reference numeral 7 denotes an oscillator for generating a reference clock for the digital signal processing circuit 6, and reference numeral 8 denotes time information recorded on the disk 2 which is separated and input by the digital signal processing circuit 6, and track skipping is performed based on its continuity. Is detected, a jump control signal for returning the position of the pickup 3 to the original position is supplied to the servo circuit 5, and a gate is provided from when the track jumps to when the pickup 3 returns to the original position. A track jump detection circuit for outputting a signal, 9 is an AND circuit, 10 is a write address counter, which counts a clock synchronized with data output from the digital signal processing circuit 6 with a pulse gated by the AND circuit 9 I do. Further, reference numeral 11 denotes a read address counter, which counts with a clock synchronized with data output from the digital signal processing circuit 6. Reference numeral 12 denotes a switch for switching the outputs of the counters 10 and 11, which is controlled by the digital signal processing circuit 6. The switch 12 selects the output of the counter 10 when writing to the memory 13, and selects the output of the counter 11 when reading. Is controlled in synchronization with the output data of the digital signal processing circuit 6. Reference numeral 13 denotes a memory, 14 denotes a DA converter for converting the output data of the memory 13 from digital to analog, and 15 denotes a sample / hold circuit which samples and holds the output of the DA converter 14 to obtain a two-channel audio signal. Next, the operation of FIG. 1 will be described with reference to the operation timing chart of the track jump detection circuit 8 of FIG. 2 and a memory map showing the contents stored in the memory 13. [0013] Pickup 3 from the track of disk 1
Is amplified by the preamplifier circuit 4,
It is applied to the digital signal processing circuit 6. The digital signal processing circuit 6 separates the time information, and transmits the time information to the track jump detection circuit 8 through the signal line 8S. Also,
The digital signal processing circuit 6 performs two-channel binary-coded 1
6-bit audio data is sampled at a frequency of 44.1 kHz.
z and alternately output to the memory 13 and synchronizing the clock with the AND circuit 9 and the read address counter 1
Feed to 1. Here, the operation of the track skipping circuit 8 is shown in FIG.
This will be described with reference to the timing chart of FIG. The time information from the digital signal processing circuit 6 is composed of minutes, seconds and frames, as indicated by 8S in FIG. 2, and the frame is in units of 1/75 seconds. When the pickup 3 accurately traces the track of the disk 1, the minute, second, and frame change sequentially and continuously, but when a track jump occurs, it becomes discontinuous. If the discontinuity is caused by the pickup 3 jumping to the preceding track, it is determined that the time is discontinuous in the increasing direction, and a jump pulse for returning the trace position of the pickup 3 to the servo circuit 5 is generated. Apply signal 8B.
By this operation, the position of the pickup 3 traces the track before the occurrence of the track jump, and the time information is shown in FIG.
8S shown in FIG. As a result, the output 8G of the track jump detection circuit 8 generates a pulse indicated by 8G in FIG. 2 from the occurrence of the track jump until the position of the pickup 3 returns. The data written in the memory 13 is controlled by the operation of the track jump detection circuit 8 described above. Next, the operation of the memory 13 will be described with reference to a memory map shown in FIG. The output data from the digital signal processing circuit 6 is binary-coded 16-bit data, and two channels are output alternately. When the track is picked up 3 being traced correctly, the chronological order _{is, L n, R n, L} n + 1, R n + 1, is output as ..... Here, if a track jump occurs at the next time point after L _{n + 3} and R _{n + 3} , the next data becomes discontinuous, and the digital signal processing circuit 6 outputs L _m , R _m , L _{m + 1} , Data output at the destination of the track jump is started in the order of R _{m + 1} ,....
The operation of the track jump detection circuit 8 causes the pickup 3
While the position is restored, the data in this section is discontinuous data. Since the write address counter 10 is stopped by the AND circuit 9 during the section of the discontinuous data, as shown in FIG.
Writes _{n + 3,} R _{n + 3} in the address 6,7, then, the digital signal processing circuit 6 is _{L m, R m, L m} + 1, but outputs the R m _{+ 1} data write operation Are not stored in the memory 3, and the writing operation is restarted when the pickup 3 returns to the original position. Thus, addresses 8 and 9 on the memory 3 are
Data continuous with _{Ln + 4} , Rn _{+ 4} , Ln _{+ 5} , Rn _{+ 5} ,... Are written. In the example shown in FIG. 3, the read address counter 11 reads out the address of the write address counter 10 with a delay of 16 addresses. This difference corresponds to the allowable value of the stop time of the write address counter 10. Therefore, the amount of difference is determined in consideration of the time required to return the pickup 3 to the original position. By increasing the capacity of the memory 3, the amount of difference can be increased. The allowable value of the stop time of the counter 10 can be increased. As described above, the contents stored in the memory 3 can be continuous data. By reading out these data sequentially and adding the data to the DA converter 14, a continuous sound is reproduced even when a track jump occurs. be able to. FIG. 4 shows another embodiment of the present invention in which the number of track jumps is not limited in the embodiment shown in FIG. In the embodiment shown in FIG. 1, the allowable value of the stop time of the write address counter 10 is limited by the capacity of the memory 3. As a result, if a track jump occurs several times, the stop time of the write address counter 10 may exceed the allowable value. In this embodiment shown in FIG. 4, an address monitoring circuit for monitoring the difference between the write address counter 10 and the read address counter 11 is provided.
Switching control can be performed so as to increase the transmission speed of reproduced data from the PC. In FIG. 4, 16 is an address monitoring circuit, 7A and 7B are oscillators, 7B is a reference clock frequency for normal reproduction speed, 7A is a reference clock for high-speed reproduction speed, and 17 Is a switch for selecting the oscillators 7A and 7B, and is controlled by the address monitoring circuit 16. Other reference numerals that are the same as those in FIG. 1 have the same functions. The operation of the embodiment shown in FIG. 4 is almost the same as that of the embodiment shown in FIG. 1, except that when the difference between the write address counter 10 and the read address The monitor circuit 16 subtracts these values and obtains an output by a decoder that detects that the value is equal to or smaller than a predetermined value, and the switch 17 controls to select the oscillator 7A. Thereby, the digital signal processing circuit 6
, And the speed detection signal of the motor 2 is proportional to this, so that the rotation speed of the disk 1 increases. As a result, the transmission speed of data reproduced from the disk 1 increases, and the data write speed of the memory 13 becomes faster than the read speed. As a result, the difference between the write address counter 10 and the read address counter 11 increases. From such an operation, even if the write address counter 10 stops due to a track jump and the difference from the read address counter 11 decreases, the data reproducing speed is increased by the address monitoring circuit 16 and the oscillator 7A. Therefore, the difference between the write address counter 10 and the read address counter 11 can always be kept at a certain amount or more. Therefore, no matter how many times a track jump occurs, the memory 1
3 is continuous, and a continuous sound can be reproduced. As described above, according to the present invention,
The time from when the reproduction main information data is written from the information storage medium using the memory to the time when the time information reproduced with the main information data is discontinuous until the information reading means returns to the original reading position. Is detected based on the continuity of the time information, and by controlling so that the reproduction main information data in this section is not written into the memory, there is an effect that the reproduction can be performed continuously even if a track jump occurs.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing an embodiment of an information storage medium reproducing device according to the present invention. FIG. 2 is a timing chart showing an operation of the track jump detection circuit in FIG. 1; FIG. 3 is a memory map diagram showing contents of a memory in FIG. 1; FIG. 4 is a block diagram showing another embodiment of the information storage medium reproducing device according to the present invention. [Description of Signs] 1 Compact disk 2 Motor 3 Pickup 4 Preamplifier circuit 5 Servo circuit 6 Digital signal processing circuit 7 Oscillator 7A, 7B Oscillator 8 Track jump detection circuit 9 AND circuit 10 Write address counter 11 Read address counter 12 Switch 13 Memory 14 DA converter 15 Sample hold 16 Address monitoring circuit

──────────────────────────────────────────────────続 き Continuation of the front page (72) Nobutaka Amada, Inventor No. 292, Yoshida-cho, Totsuka-ku, Yokohama-shi, Kanagawa Pref. ) Surveyed field (Int.Cl. ⁶ , DB name) G11B 20/10

Claims (1)

(57) [Claims] The main information data is divided into a plurality of pieces, and the divided main information data is added with identification information indicating the continuity of the divided main information data, and the identification information indicating the continuity of the divided main information data Is recorded on an information recording medium such that is continuous, and information including the divided main information data and identification information indicating the continuity of the divided main information data is taken from the information recording medium, and a recording format is obtained. Digital signal processing means for performing error detection and correction processing in accordance with the following, storing the main information data subjected to the error correction processing by the digital signal processing means in a predetermined address order, and receiving the error corrected main data from the digital signal processing means. Storage means connected to receive the information data output as input, and identification information indicating continuity of the divided main information data taken from the information recording medium When the discontinuity occurs, the reading position on the information recording medium is returned to the reading position on the information recording medium before the occurrence of the discontinuity, and the identification information indicating the continuity of the divided main information data. Between the occurrence of the discontinuity and the return to the reading position on the information recording medium before the occurrence of the discontinuity, the write address to the storage means is not advanced, and error correction processing is performed by the digital signal processing means. is the main information data stored in the storage means, where
An information storage medium reproducing apparatus, further comprising control means for performing reading control in accordance with a predetermined address order .